While the money might be a problem particularly if you back has affected you ability to work, air ride seats are a poor substitute fora mower with actual suspension.
There are some made with proper suspension.
The air ride seats are made for construction equipment like skid steers and are priced accordingly .
A poor mans substitute is a basket ball partially inflated slipped under the seat base .
The first one is a suspension kit thats goes under your existing seat. About $150. Rises your height about 1 1/2". Unless you fabricate height accordingly.
Second is a full suspension seat. About $325. You'll have to fabricate new mounting to compensate ride height.
I have both and my bad back says either one is worth it..!
BTW.. The second one pictured is mounted on a ZT woods as shown in my avatar at left.
That suspension works great for me.
There's a couple "buts"
There's only 1" of travel which works for me (170#). But I'm thinking for someone 250# or better it may bottom out more. IDK. The spring rate is adjustable though so it may be just fine.